[PATCH] lower-bitint: Fix ICE on bitint-39.c

[PATCH] lower-bitint: Fix ICE on bitint-39.c

[Jakub Jelinek]

Hi!

torture/bitint-39.c ICEs with -O1; the problem is that the
finish_arith_overflow code in one spot replaces use_stmt with an
assignment or cast, but if unlucky and m_gsi iterator is the same statement,
when the code later
      tree clobber = build_clobber (TREE_TYPE (var), CLOBBER_EOL);
      g = gimple_build_assign (var, clobber);
      gsi_insert_after (&m_gsi, g, GSI_SAME_STMT);
it will insert after iterator which contains already replaced statement and
that causes the gimple chain corruption.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok
for trunk?

2023-12-01  Jakub Jelinek  <jakub@redhat.com>

	* gimple-lower-bitint.cc (bitint_large_huge::finish_arith_overflow):
	When replacing use_stmt which is gsi_stmt (m_gsi), update m_gsi to
	the new statement.

--- gcc/gimple-lower-bitint.cc.jj	2023-11-30 10:57:40.095555940 +0100
+++ gcc/gimple-lower-bitint.cc	2023-11-30 12:46:34.715093396 +0100
@@ -3682,6 +3682,8 @@ bitint_large_huge::finish_arith_overflow
 	      else
 		g = gimple_build_assign (lhs2, NOP_EXPR, ovf);
 	      gsi_replace (&gsi, g, true);
+	      if (gsi_stmt (m_gsi) == use_stmt)
+		m_gsi = gsi_for_stmt (g);
 	      break;
 	    }
 	}

	Jakub

Re: [PATCH] lower-bitint: Fix ICE on bitint-39.c

[Richard Biener]

On Fri, 1 Dec 2023, Jakub Jelinek wrote:

> Hi!
> 
> torture/bitint-39.c ICEs with -O1; the problem is that the
> finish_arith_overflow code in one spot replaces use_stmt with an
> assignment or cast, but if unlucky and m_gsi iterator is the same statement,
> when the code later
>       tree clobber = build_clobber (TREE_TYPE (var), CLOBBER_EOL);
>       g = gimple_build_assign (var, clobber);
>       gsi_insert_after (&m_gsi, g, GSI_SAME_STMT);
> it will insert after iterator which contains already replaced statement and
> that causes the gimple chain corruption.
> 
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok
> for trunk?

OK.

> 2023-12-01  Jakub Jelinek  <jakub@redhat.com>
> 
> 	* gimple-lower-bitint.cc (bitint_large_huge::finish_arith_overflow):
> 	When replacing use_stmt which is gsi_stmt (m_gsi), update m_gsi to
> 	the new statement.
> 
> --- gcc/gimple-lower-bitint.cc.jj	2023-11-30 10:57:40.095555940 +0100
> +++ gcc/gimple-lower-bitint.cc	2023-11-30 12:46:34.715093396 +0100
> @@ -3682,6 +3682,8 @@ bitint_large_huge::finish_arith_overflow
>  	      else
>  		g = gimple_build_assign (lhs2, NOP_EXPR, ovf);
>  	      gsi_replace (&gsi, g, true);
> +	      if (gsi_stmt (m_gsi) == use_stmt)
> +		m_gsi = gsi_for_stmt (g);
>  	      break;
>  	    }
>  	}
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)